The electrophilic/nucleophilic character of a series of captodative (CD) ethylenes involved in polar cycloaddition reactions has been studied using DFT methods at the B3LYP/6-31G(d) level of theory. The transition state structures for the electrophilic/nucleophilic interactions of two CD ethylenes toward a nucleophilically activated ethylene, 2-methylene-1,3-dioxolane, and an electrophilically activated ethylene, 1,1-dicyanoethyelene, have been studied, and their electronic structures have been characterized using both NBO and ELF methods. Analysis of the reactivity indexes of the CD ethylenes explains the reactivity of these species. While the electrophilicity of the molecules accounts for the reactivity toward nucleophiles, it is shown that a simple index chosen for the nucleophilicity, Ν, based on the HOMO energy is useful explaining the reactivity of these CD ethylenes toward electrophiles.

Understanding the reactivity of captodative ethylenes in polar cycloaddition reactions. A theoretical study.

Captodative olefins 1-acetylvinyl carboxylates proved to be highly regioselective dipolarophiles in 1,3-dipolar cycloadditon to propionitrile oxide, arylphenylnitrile imines, diazoalkanes, and nitrones to yield the corresponding 5-substituted heterocycles. The addition of the latter was also stereoselective, being slightly susceptible to steric demand of the carboxylate substituent in the olefin. All atempts to cleave the isoxazolidine N−O bond under reductive conditions failed, providing diverse products with side-group reduction. FMO theory was unsuccessful to explain the regioselectivity observed with nitrones, since the opposite orientation was predicted. The recently formulated DFT/HSAB theoretical model was able to rationalize this regioselectivity, identifying the nucleophilic and electrophilic atoms involved in the process via calculation of interaction energies, suggesting the specific direction of the electronic process at each of the reaction sites.

Regio- and stereoselectivity of captodative olefins in 1,3-dipolar cycloadditions. A DFT/HSAB theory rationale for the observed regiochemistry of nitrones

Synthesis of α-ketols by functionalization of captodative alkenes and divergent preparation of heterocycles and natural products

A catalytic acylation of vinylsilane with acid anhydride is accomplished by the use of [RhCl(CO)2]2, in which the transmetalation between vinylsilane and rhodium(I) carbonyl complex plays a key rol...

Rhodium-Catalyzed Acylation of Vinylsilanes with Acid Anhydrides

https://www.repositoriodigital.ipn.mx/bitstream/123456789/8534/1/Articulos%20ISI%20CarmenCruz-6.pdf

Captodative olefins: methyl 2-aryloxy-3-dimethyl- aminopropenoates and their application in a new synthesis of benzofurans

Influence d'une catalyse par des acides de Lewis (ZnCl 2 , BF 3 •Et 2 O) sur la regioselectivite de la reaction. Le stereoisomere endo est majoritaire a 80%

Alfredo H. Munoz

Papers

Highly selective Diels-Alder cycloadditions of captodative dienophiles 1-acetylvinyl arenecarboxylates to unsymmetrically substituted butadienes

Highly Selective Diels-Alder Cycloadditions of Captodative Dienophiles 1-Acetylvinyl Arenecarboxylates to Unsymmetrically Substituted Butadienes.